The present invention generally relates to a film valve assembly and, more particularly, to a film valve assembly for a heating, ventilation and air conditioning system for a vehicle.
Conventional heating, ventilation and air conditioning (HVAC) systems for vehicles generally include a housing, an evaporator, a heater core having a housing, an evaporator assembly coupled to the housing, an evaporator, a heater core, an air inlet, a fan and various doors or mode valves for controlling the volume and direction of air flow and generating outlet air of a desired volume and temperature. Together these components receive, temper and direct the flow of forced air through several outlets or vents in the vehicle. The outlets through which the forced air ultimately exits are determined by the various doors which rotate or swing back and forth to open or close off openings and passages and cause air flow to be forced in one direction or another or a combination of both. Air may be directed to various areas of the car depending on the state of the mode valves. For example, air may be forced through outlets directed at the windshield in a defrost or defog mode, or through outlets directed at mid-height level in an air-conditioning mode, or to lower outlets directed to the floor in a heat mode, or various combinations thereof. Although, air of any temperature may be directed to and through any of them.
More recently, designs utilizing a flexible film valve rather than doors have been proposed for controlling volume and direction of air flow. Generally, the flexible film valve is disposed in a frame having rollers. The flexible film valve includes various apertures formed therein, is rolled back and forth over a first roller to cover or uncover various openings and may include an actuator for controlling the roller to wind and unwind the film valve.
Typical film valve designs are disclosed in U.S. Pat. No. 5,160,115 to Ito, et al. and U.S. Pat. No. 6,273,811 B1 to Pawlak, III. The ""115 patent discloses an HVAC assembly including a film valve assembly having one roller with a biasing member and a motor. The ""811 patent discloses an HVAC assembly including a film valve assembly having two rollers, each with a biasing member and a motor, and each operating a separate film valve. Such designs cause excessive wear on the film valve, the roller and the actuator, thereby increasing costs, and introduce noise in the system due to increased operational efforts required which may be displeasing to the driver of the vehicle.
In addition, the frame in which the film valve is situated typically comprises a static design specifically manufactured to be fitted onto an HVAC housing. Therefore, a frame must be designed and manufactured to meet each HVAC housing design, thereby increasing engineering and tooling cost.
The present invention is aimed at solving one or more of the problems described above.
In one aspect of the present invention, a film valve assembly is provided for a heating, ventilation and air conditioning (HVAC) system for a vehicle having a housing including apertures and ribs, an evaporator assembly, and a heater assembly. The film valve assembly includes a frame disposed on the housing for defining an air mixing chamber therebetween, a first roller disposed on the frame, a first biasing device continually urging the first roller to rotate in a first direction under a first constantly applied force, a second roller disposed on the frame, a second biasing device continually urging the second roller to rotate in a second direction under a second constantly applied force, and a film valve extending between the rollers with a first end disposed on the first roller and a second end disposed on the second roller.
In another aspect of the invention, the film valve assembly further includes a cap disposed on the frame and having one of the first and second rollers disposed thereon.
In yet another aspect of the invention, the film valve assembly includes a frame having a first segment and a second segment and a first hinge assembly for rotatably coupling the first and second segments. The film valve assembly may further include a frame having a third segment and a second hinge assembly for rotatably coupling the third segment to one of the first and second segments.
In another aspect of the invention, the first and second rollers each include an axle having a first distal end and a second distal end, a cylinder having a hollow end and a beveled end with the axle being disposed on the hollow end and extending therefrom, a shaft disposed on the beveled end. The rollers are disposed on the beveled end with the shaft disposed thereon. Each roller further includes a biasing device continually urging its respective roller to rotate in a direction under a constantly applied force. An actuator providing non-constant force is coupled to one of the first and second rollers for providing rotational torque to the roller.
The several embodiments of the present invention provide advantages including a more efficient, less expensive, quieter film valve assembly. The film valve assembly may be adapted to be used with several HVAC assembly configurations, thereby decreasing engineering and tooling costs.